elektronegatívny

Elektronegativity is a chemical property that describes the tendency of an atom to attract a shared pair of electrons (also known as bonding electrons) towards itself in a covalent chemical bond. This property is not directly measured but is instead calculated based on various other chemical properties of atoms. The concept of electronegativity was first introduced by Linus Pauling in 1932, who developed a relative scale to quantify this tendency.

The electronegativity of an element is influenced by its atomic structure, specifically the number of valence electrons and the distance of these electrons from the nucleus. Elements with a greater effective nuclear charge and a smaller atomic radius tend to be more electronegative. For example, fluorine, the most electronegative element, has a high effective nuclear charge and a small atomic size, allowing it to strongly attract electrons. Conversely, elements like cesium and francium, which are located at the bottom left of the periodic table, are the least electronegative, having large atomic radii and weaker attractions for electrons.

Electronegativity values are typically reported on scales such as the Pauling scale, the Mulliken scale, or the Allred-Rochow scale. The Pauling scale is the most commonly used, with values ranging from approximately 0.7 for francium to 3.98 for fluorine. When two atoms with different electronegativities form a covalent bond, the electrons in the bond will be pulled more towards the more electronegative atom. This unequal sharing of electrons results in a polar covalent bond, where one atom develops a partial negative charge and the other develops a partial positive charge. The greater the difference in electronegativity between the bonded atoms, the more polar the bond will be. If the electronegativity difference is very large, the bond will be considered ionic rather than covalent.